Method of and means for cooling brakes



Aug. 22, 1933. L. c. HUCK METHOD OF AND MEANS FOR COOLING BRAKESOriginal Filed 2 1925 5 Sheets-Sheet 1 L. c. HUCK 1,924,060.

Aug. 22, 1933.

METHOD OF AND [MEANS FOR 000mm BRAKES Original Filed Dec. 26, 1925 5Sheets-Sheet 2 I L. C. HUCK Aug. 22, 1933.

Original Filed'Dec. 26, 1925 5 Sheets-Sheet 3 Aug. 22, 1933. 1.. c. HUCK1,924,060

' METHOD OF AND MEANS FOR COOLING BRAKES Original Filed Dec. 26. 1925 5Sheets-Sheet 4 loans 6. flan/i,

Aug 22, 1933. c HUCK 1,924,060

METHOD OF AND MEANS FOR COOLING BRAKES Original Filed 1925 5Sheets-Sheet 5 Joan aflizck/ 5/ ,[77 z/rzforr.

Patented Au 22,- 1933 amnion or MEANS FOR COOLING BRAKES g Louis 0.HuckQNew York, N. Y.

Refile for abandoned application Serial No".

77,733, December 26,

1925. This application March 31, 1930. Serial No. 440,524

6 Claims. (01. 188-264) 1 This invention relates to method of and meansfor cooling brakes and adjacent parts, and more particularly to suchmethod and means when the brakes are housed within one of the dual discwheels very frequently used on heavy motor vehicles.

As is well known in the automotive industry brakes haveheretofore been asource of trouble when required to absorb large amounts of'energy in'acomparatively short interval of time,

due to the results of the high temperatures of the braking mechanismresulting under such conditions. One of the results referred to above isthe lowering of the coeflicient of friction of the average present dayfabric brake liners with the attendant reduction of the braking actionresulting from a given force or effort applied to the brakeactuatingmean's. Another result is the more rapid wear and shorteruseful life of such fabric brake liners. Another such result is theshorter life of the tires when the brake mechanism is housed in theconcave side of a disc wheel.

In'most states legislation limits over all width of vehicles. Forstability, riding qualities and efiiciency it is desirable to mountroadsprings on the axle as far apart as possible. The spacing of roadsprings is limited by interference of road springs or spring clips withbrake mechanism, or with wheels or tires if the brake mechanism ishoused inside of a wheel. Heavy vehicles mounted on pneumatic tiresfrequently use dual rear tires mounted on disc wheels.

In order to allow wide spring spacing, the brake drums of such vehiclesare usually mounted inside of the inner disc wheel. It is desirable touse as large diameter of brake drum as possible in order to get greaterbraking, action and longer life. The disadvantage, however, of so doingis that the air space between the brake drum and the rim of the innerwheel becomes too small to allow much circulation of air. The air inthis air space becomes heated and the heat transfer from the brake drum.to the air surrounding it decreases, resulting in increased temperatureof brake drums for a given amount of heat generated by friction. Theheat thus generated is transferred to the wheel rim by conductionthrough disc of wheel and by radiation and also by convection by andconduction through the heated air in the space between the brake drumand the rim, and thence to the tire.

This heating of the tires is extremely 'undesirable as it shortens thelife of the tires and in extreme cases causes devulcanizing or softeningof the rubber with attendant blowouts.

Among the objects of my invention is to provide a method of and meansfor causing a. forced circulation of cool air through the air spacebetween the brake drum and the rim, thus increasing the escapeof heatedair from around the brake drum to the outside air, and consequentlyreducing the temperature of the drum, since by the constant 5 supply ofcool air to the air space between the drum and rim the air therein iskept comparatively cool, and avoids that part of the transfer of heat to,the rim (and thence to the tire) broughtabout by convection by andconduction 7o throughthe. air in the space between drum and rim.

The introduction of such a current of cool air through the space betweenthe brake drum and rim will cool the'rim by carrying away some of theheat transferred to the rim from the drum by radiation. Such a transferof heat (i. e. transfer by radiation) from drum to rim can also bereduced by polishing these .parts or by other means reducing thecoeflicients of absorption and g emission.

A further object is to circulate a current of air around the. brakemechanism for carrying away the heat generated by the brake drum toincrease the life of the brake linings and tires, and to avoid adecreasev in the coefiicient of friction of the brake liner due to hightemperatures, thereby avoiding a decrease in sensitiveness of the brakesby reason of their absorbing a large amount of energy in a comparativelyshort interval of time. 9

A further object is to prevent undue scoring of the brake drums.

Other objects, advantages and capabilities will more readily becomeapparent as the following description proceeds.

My inventionfurther resides inthe combination, construction andarrangement of parts illustrated in the accompanying drawings, and whileI have shown therein a preferred embodiment I wish it to be understoodthat the same is sus- 10o ceptible of modification and change withoutdeparting from the spirit of my invention.

. -In the drawings: 'Fig. 1 is a sideelevation partly broken awayshowing wheels and brake mechanism looking 105 outwardly from the centerof a vehicle chassis.

Fig. 2 is a vertical sectional view taken on the line 2-2 of Fig. 1. y

Fig. 3 is a vertical section on a plane between the two disc wheels andshowing in side elevation no the impeller or rotor.

Fig. 4 is a view similar to Fig. 2 but showing a modification in whichthe impeller or rotor is omitted.

' Fig. 5 is a fragmentary section through a portion of the wheel showinga modification.

Fig. 6 is an elevation of the impeller disc plate used in this modifiedform.

Fig. '7 is an elevation of the wheel disc ofthis modification.

Fig. 8 is a section through the hub of this modifled form and showing inelevation the hub flange and the attached brake drum.

Fig. 9 is a sectional view partly broken away through the cover plate23, taken on a plane passing through one of the hooked bolts 24 and wingnut 25. I

Fig. 10 is a fragmentary sectional view taken on the line 1010 of Fig.9.

Fig. 11 is a section taken on the line 1111 of Fig. 9.

For the purpose of illustration the mechanism embodying my invention isshown in the drawings in connection with dual disc wheels equipped withpneumatic tires, and the brakes shown are of the internal expandingtype; It is obvious, however, that my invention is not restricted in itsuse to this particular construction of either brake or brake drumhousing, but may be utilized in other embodiments involving the problemssolved herein.

Referring to the drawings, the outer disc wheel 1 and the inner discwheel 2 are mounted on hub 3 and rotated therewith through the medium ofstuds or bolts 4. ,Hub 3 rotates on bearings b mounted on tube 5, whichis pressed into and supported by housing 6. Axle shaft 7 serves torotate the hub 3 through the medium of drive plate 8 and bolts 9,respectively. The axle shaft is rotated by a source of power throughsuitable power transmission mechanism not shown. Rims 10 and 11 aremounted on and in this illustration form an integral part of disc wheels1 and 2, respectively. Outer and inner tires 12 and 13 are mounted onrims l0 and 11, respectively, rim 10 being provided with depression 14,and rim 11 with depression 15, through which depressions the inner tubevalves 16 extend. Access to valve 16 is had through ports 17 provided indisc wheels 1 and 2. Each wheel has two such ports so located withreference to the holes for driving studs 4 that the wheels areinterchangeable, thus permitting the outer wheels to be always capableof being so mounted that there is a port opposite the inner wheel valve.

The brake drum .18 is a fastened to hub 3 by bolts 19 passing through acircular flange provided on hub 3, as shown in Fig. 2. Within the brakedrum 18 are suitably mounted brake shoes 20, which can be brought intofrictional contact with the brake drum 18 by means of cam 21 (seeFig. 1) or other suitable actuating mechanism. Brake shoes 20 are pulledout of engagement with drum 18 through the action of springs 22 uponrelease of the cam or actuating mechanism 21. Each of the brake shoes isprovided on its active face with the usual brake lining 1. In order tokeep dust, dirt and other foreign matter out of the brakes the dustshield 29 is provided on the inner face of the brake drum, as shown inFig. 2.

Ports 17 in the outer wheels are closed substantially air-tight by coverplates 23, suitable means being provided for holding these cover platesagainst the disc wheel. In the particular embodiment shown in thedrawings these cover disc wheel the hook bolts can then be rotatedthrough a sufficient angle to move their angular ends into engagementwith the inner face of the disc wheel, after which the nuts 25 may besuit ably tightened, which tightening operation will draw that portionof the bolt which is squared in cross-section into engagement with thesquare holes, to thereafter prevent any accidental turning of the hookbolts to permit the cover plate to become loosened. To remove thesecover plates it is only necessary to loosen nuts 26 until the hookbolts'can be moved inwardly suificiently to carry the square section outof the square holes, after which the hook bolts can be rotated inwardlyto clear the disc wheel and permit removal of the cover plate.

Secured between disc wheels 1 and 2, and also securely held therebetweenby studs 4, is the disc plate 26, which, as seen in Figs. 2 and 3, isprovided at suitably spaced intervals around its perimeter with impellerblades 27, for the purpose of causing a more positive movement of theair in the space between the disc wheels and tires. These impellerblades 27 are preferably made of rubber, leather, or other suitable softma terial to avoid injury to the blades or tires in case one or both ofthe tires become fiat. These impeller blades are also preferablyprovided with stiffening ribs 28. The disc plate 26 is also providedwith suitable openings h to allow access to valves of the inner tire.

In the operation of the device the impeller blades 27 impart a rotarymotion to the air in the marginal space between the disc wheels and '120between the tires as the wheels revolve. The centrifugal force set up bythe rotation of this body of air throws the air out between the tires asin any centrifugal air blower, thus lowering the air pressure within thespace. As there are no openings for the air to get into this spacethrough the outer wheels all of the air displaced by this centrifugalforce must enter this space through the port holes 17 in the inner discwheel, and in order to reach these ports it must enter between the innerwheel rim and brake dust shield 29, and pass over the brake drums,absorbing during its passage heat from the brake drums, which heat iscarried away by this current of air, resulting in a cooling of the brakedrum. This current of air also serves to cool the rim in several ways,first, by directly carrying the heat away therefrom, and second, byreducing the amount of heat radiated from the drum to the rim by reasonof the lower drum temperature brought about by this circulation of air,and third, by decreasing the conduction and convection of heat by theair in the space between the drum and rim.

In the modification shown in Fig. 4 I have omitted the impeller or rotor26 and depend upon the surface friction to carry the air around with thewheel which air, when the wheel has gotten well in motion, will acquiresufllcient Velocity to cause it to be thrown out from between the twodisc wheels and tires by centrifugal force, resulting in the drawing ofair inwardly over the brake drum with the cooling effect describedabove.

It is obvious that the amount the mechanism is cooled depends on thetemperature and volume of air passing through the space between the drumand the rim, and also on the amount of surface exposed to this currentof air. The surface to be cooled can be increased by adding ribs or fins30 as shown in Figs. 5 and 8, to the outer circumferential face of thebrake drum 18. These ribs can be made integral with the brake drum orattached thereto by means of a band 31, as desired.

To increase the surface available the construction shown in Figs. 5-8may also be used, wherein the ports 17 of the inner wheel are alsoclosed oil by any suitable means such as a depressed cap 32 toaccommodate the valve stem, and the air rim is drawn downwardly throughthe space 33,

' the passageways 34 (formed on the outer face of the flange 35 of hub3), from thence through holes 36, and then upwardly through slots 37(formed in impeller disc plate 26') and into the space between thetires, from which space the air will be thrown bycentrifugal force asexplained above. Thepassageways 34, the holes 36, and the slots'37 willbe so positioned with relation to the holes for the bolts 4 that theywill be in registry to form a continuous passageway when the parts areassembled. In this form of construction it will be noted that the airbefore reaching the holes 36 and slots 3'7 must pass not only over thebrake drum perimeter, but also between the back face of the brake drumand the inside face of the disc of the inner wheel, thus furtherincreasing the surface exposed to the cooling action of the air current.Openings 38 are also provided in disc plate 26' to permit access to thevalve stem of the tire.

This application is a refiling of abandoned application Serial Number77,733, filed December 26, a

- outside air.

2. In apparatus of the class described a pair of wheels secured togetherand having an annular space around their outer portion, a brake drum inone of said wheels, a rim spaced from said drum, the space between thedrum and rim having connection on one side with the outside air andconnection on the other side with the annular space, and means in theannular space to cause the air therein to rotate therewith so that saidlast mentioned air will be thrown out from the annular space bycentrifugal force and cause a positive circulation of air across thebrake drum for cooling D D 3. In apparatus of the class described, brakemechanism, associated parts forming a substantially circular airenclosure arranged to rotate with the rotating part of the brakemechanism, said parts having an opening at the outer periphery of saidair enclosure, and an air passage connecting the air enclosure with theair space surrounding the peripheral exterior of the brake mechanismtopermit the ,flow of air over the brake mechanism and out through the airen-,

closure for cooling the brake, and means to cause the air to rotatewiththe air enclosure until thrown therefrom by centrifugal force.

4. A dual disc wheel comprising inner and outer wheels secured together,a rim and tire on each wheel, brake mechanism housed in one of thewheels, ports in each of said wheels, and means for sealing the ports inone of the wheels to cause the flow of air through the other ports andover the brake mechanism for cooling purposes, and means for creating asuction through said other ports to set up a positive flow of the air.

5'. In apparatus of the class described, a pair of disc wheels securedtogether, a rim and tire on each of said wheels so arranged as to forman annular airspace around said wheels, a brake mechanism in one of saidwheels, and a series of impellers carried by said wheels to extend intosaid annular air space to cause the air therein to rotate with thewheels until thrown out from between the tires by centrifugal force toproduce a flow of air across the brake mechanism to cool the same.

6. A dual disc wheel comprising inner and outer wheels secured together,a brake mechanism housed in one of said wheels, an impeller disc platesecured between the disc wheels, a supporting member to which the discwheel and the brake drum are secured, said supporting member havingradial grooves each communicating at one end with the space between thebrake drum and wheel rim and at the other with a transverse openingthrough the wheel disc,'a plurality of radial slots in said disc plateeach registering at one end with one of said transverse openings andextending at its other end into communication with the space between thetires, so that air will be drawn over the brake drum and rim, throughsaid grooves, openings and slots, and discharged from the space betweenthe tires by centrifugal

